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Forms of energy involved in soil formation
Winfried EH Blum
Institute of Soil Research, University of Natural Resources and Applied Life Sciences Vienna, Austria, Europe, Email
[email protected]
Abstract
Four different forms of energy involved in soil formation are described: gravity, orogenic energy, solar
energy and anthropogenic energy, in order to understand and to measure soil formation under different
physio-geographic and environmental conditions.
Key Words
Soil formation, forms of energy, weathering, critical zone research
Introduction
Soils are providing goods and services of paramount importance for sustaining human societies and the
environment (Blum, 2005; Frossard et al., 2006; Costanza et al., 1997).
In view of the world wide losses of soil, e.g. through erosion, information about the time scale of soil
formation becomes increasingly important (European Commission 2006). Until today, we have
measurements and assessments regarding soil losses, but no solid data about the pace of soil formation.
Therefore, the question arises: How much soil is formed with time, under different climatic, geological,
topographical, hydrological and biotic conditions, under the influence of human activities, including climate
change. An international research group on critical zone processes is targeting this issue (Chorover et al.,
2007).
Methods
For answering this question, a first approach could be to identify the basic forms of energy involved in soil
forming processes. With such an approach, it would also be possible to develop a comprehensive concept,
which would allow to describe processes of soil formation as well as methods to measure them, e.g.
weathering of rock parent material and the development of the regolith zone, as well as the further
development from regolith to soil. This concept could also allow to define indicators for the different
characteristics of rock, regolith and soil.
Results
Soil formation is driven by four main forms of energy: gravity, orogenic energy, solar energy and
anthropogenic energy. Gravity influences all movements of solid, liquid and gaseous materials. It is an
inherent form of energy and influences the vector and the velocity of fluxes within soils as well as at their
surface. – Gravity is also the main factor of morphogenesis.
Orogenic energy is the second form of energy and is herited from the rock parent material, which was
formed through orogenesis, an endogenic process which created very diverse types of rocks and minerals
under high temperature and pressure. This endogenic energy, which can also be called orogenic energy, is
still contained in rocks and in the rock forming minerals. This energy is normally not renewed for a long
time, except in cases such as volcanic activities and others. – Through exogenic forces, derived from solar
energy, e.g. through processes of weathering and transport (e.g. erosion), this orogenic energy pool is
constantly lowered. Primary minerals, such as micas and feldspars contain more energy, derived from
orogenesis as their weathering products, e.g. clay minerals and oxides. Moreover, the resistance of different
minerals against weathering or the buffer capacity of soils against acidification can also be explained by
orogenic energy. Orogenic energy is manifest in the texture and structure of rocks and the crystallography of
minerals and their resistance to exogenic forces, which is mainly explained by the form and density of the
mineral package in the rocks or the element package in the crystal structure of minerals. – Orogenic energy is
also manifest in the chemical composition of minerals, which plays an important role, e.g. through the
content of alkaline and earth alkaline cations in relation to silica, aluminium and metals such as iron,
manganese, copper, zinc and others.
© 2010 19th World Congress of Soil Science, Soil Solutions for a Changing World
1 – 6 August 2010, Brisbane, Australia. Published on DVD.
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Solar energy is the third form of energy, deriving directly from solar radiation or from diffuse radiation
through reflection and indirectly from organic matter and biomass, which can be considered as a secondary
form of solar energy, with a different dimension in space and time. Both, direct and indirect forms of solar
energy e.g. organic matter are the basis of exogenic forces, driving biochemical and physico-chemical
processes in soils. – Solar energy also influences the velocity of bio-physico-chemical reactions. – In the
past, soils developed under different climatic conditions (paleoclimates), especially in the tropics and subtropics, which makes it difficult to use current climatic data, such as temperature and/or precipitation to
explain soil formation.
Anthropogenic energy is the fourth form of energy, deriving from anthropogenic activities. It is a mixture of
different energy forms, including human labour, and is mainly based on fossil energy and non-renewable
resources, such as oil, coal, rocks and minerals.
Since the end of the 18th century, anthropogenic influences on terrestrial and aquatic ecosystems have been
exceeding the natural impacts (Crutzen, 2002; Blum and Eswaran, 2004).
Conclusions
In order to understand soil formation under different environmental, social, economic, technical and cultural
conditions, it seems to be interesting to use the energy concept in order to make soil formation
understandable and measurable. This is the current task of the critical zone approach.
References
Blum WEH (2005) Functions of Soil for Society and the Environment. Reviews in Environmental Science
and Biotechnology 4, 75-79.
Blum WEH (2008) Forms of energy involved in soil and sediment processes. J. Soils Sediments 8(1), 1-2.
Blum WEH, Eswaran H (2004) Soils and sediments in the anthropocene. J. Soils Sediments 4(2) 71.
Costanza R, d'Arge R, de Groot R, Farber S, Grasso M, Hannon B, Limburg K, Naeem S, O'Neill RV,
Paruelo J, Raskin RG, Sutton P, van den Belt M (1997) The value of the world's ecosystem services and
natural capital. Nature 38, 253-260.
Chorover J, Kretzschmar R, Garcia-Pichel F, Spraks DL (2007) Soil biogeochemical processes within the
Critical Zone. Elements 321-326.
Crutzen PJ (2002) Geology of mankind. Nature 415, 23.
European Commission (2006) Thematic Strategy for Soil Protection. COM(2006)231 final.
Frossard E, Blum WEH, Warkentin BP (Eds.) (2006) Function of Soils for Human Societies and the
Environment. Special Publication No. 266, Geological Society, London (ISBN 978-1-86239-207-6).
Warr B, Ayres R (2004): Accounting for soils: Towards an integrated sustainability and productivity
asessment for soils. INSEAD, CMER, 1-11, Fontainbleau, France.
© 2010 19th World Congress of Soil Science, Soil Solutions for a Changing World
1 – 6 August 2010, Brisbane, Australia. Published on DVD.
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